Answer:
1,2,4
Explanation:
Okay so basically in a triangle, the sum of any two sides should be greater than the third remaining side. So if we had a triangle with sides A, B, and C, A+B>c, A+C>B, and B+C>A. If you look at 1,2, and 4, 1=2=3 which is less than 4. That is why that is not a triangle.